The coupling between a drive and its driven member is exposed to considerable pressures and stresses and as a result frequently requires servicing and/or replacement. Indeed, couplings serve as a link between a drive means and a driven member and are frequently formed of materials such as metal and the like which are responsible for the transfer of considerable stresses, including torsional and vibrational stresses, produced between the coupling and the driven member along the drive train thus resulting in the stressing and wear of the coupling and other parts which can be costly and time consuming to repair or replace.
Further, when a drive is semi-permanently coupled to its corresponding driven member, disengaging the coupling (and as such the engine) from its driven member can be a complex and time consuming task requiring the apparatus to be broken down in order to gain access to the coupling to effect the disengagement.
Another problem with coupling arrangements is running contact which results in the wearing of components due to friction. Running contact during the engagement of the drive means with a driven member is clearly undesirable and can greatly affect the working life of the coupling. Present methods for dealing with the problem of running contact are less than adequate.